I have created some code clips (in German language) for Microsoft MSDN to show how to access SAP data in .NET using LINQ to SAP from Theobald Software. The clips will show how to display SAP data in Silverlight using ADO.NET Data Services and LINQ to SAP. You may visit the website MSDN-Solve.de and search for SAP or just click the following links:

A lot has been written about Microsoft’s new data access technology LINQ (Language Integrated Query) since the first preview version has been published. But there are still some interesting aspects to LINQ and its extensibility. This article will introduce a new provider called LINQ to SAP which offers an easy way to retrieve business data from SAP/R3 systems within a .NET application.

With the introduction of the .NET framework 3.5 and the programming language extensions for C# and VB.NET Microsoft began to redefine the way developers would implement data access. Nearly all applications today are querying data from different data sources. Mainly those data sources are SQL databases, XML files or in-memory collections. LINQ offers an universal and standardized approach to access all those data sources using special data providers. The LINQ language syntax strongly resembles that of SQL. The following sample shows how to query data from a string array with LINQ:

string[] names = {„John“, „Patrick“, „Bill“, „Tom“}

var res = from n in names where n.Contains(„o“) select n;

foreach(var name in res) Console.WriteLine(name);

This simple LINQ query based on an in-memory collection (array) selects all items in the array „names“ that contain the letter „o“. Console output: „John, Tom“. A LINQ introduction is beyond the scope of this article. A very good introduction article can be found on CodeProject.com.

LINQ Providers

The .NET framework comes with built-in providers for collections and lists (LINQ to Objects), for Microsoft SQL Server databases (LINQ to SQL), for XML files (LINQ to XML) and finally for DataSet object instances (LINQ to DataSet). Beside the standard providers, developers can extend LINQ by creating custom providers to support special data sources. LINQ to LDAP or LINQ to Amazon are examples of such custom providers.

To write a custom LINQ provider one must basically implement two interfaces: IQueryable and IQueryProvider. These interfaces make objects queryable in LINQ expressions. Developing a LINQ provider can be a very complex task, but there a quite some good blog entries on the net explaining the steps in detail.

This article will introduce a new provider called LINQ to SAP from Theobald Software which provides developers with a simple way to access SAP/R3 systems and their data objects. The software also provides a Visual Studio 2008 Designer to define SAP objects interactively and integrate them in .NET applications.

SAP Background

This section will give you a short explanation and background of SAP objects that are queryable by LINQ to SAP. The most important objects are Function Modules, Tables, BW Cubes and Queries.

A Function Module is basically similar to a normal procedure in conventional programming languages. Function Modules are written in ABAP, the SAP programming language, and are accessible from any other programs within a SAP/R3 system. They accept import and export parameters as well as other kind of special parameters. The image below shows an example of a Function Module named BAPI_EQUI_GETLIST within the SAP Workbench:

Figure 1: Function Module (SAP Workbench)

In addition BAPIs (Business-API) are special Function Modules that are organized within the SAP Business Object Repository. LINQ to SAP also allows access to SAP tables. Those are basically straightforward relational database tables. Furthermore the LINQ to SAP Designer allows developers to define and access BW Cubes (Business Cube Cubes) and Queries (SAP Query). BW Cubes are also known as OLAP Cubes. Data are organized in a multi-dimensional way within a cube. SAP Queries work just like other queries. To indentify a SAP Query uniquely there are three pieces of information necessary: user area (global or local); user group and the name of the query. With the concept of Queries SAP provides a very simple to generate reports, without the need of knowing the SAP ABAP programming language.

Visual Studio 2008 Designer for LINQ to SAP

In order to use LINQ to SAP and the associated Visual Studio Designer, the .NET library ERPConnect.net from Theobald Software must be installed first. This software is the basic building block between .NET and a SAP/R3 system and provides an easy API to exchange data between the two systems. The company offers a free trial version to download. After installing ERPConnect.net, LINQ to SAP must be installed separately using a setup program (see manual). The provider and the designer are actually extensions to the ERPConnect.net library. The LINQ to SAP provider itself consists of the Visual Studio 2008 Designer and additional class libraries that are bundled within the namespace ERPConnect.Linq.

The setup adds a new ProjectItem type to Visual Studio 2008 with the file extension .erp and is linking it with the designer. Double-clicking the .erp-file will open the LINQ to SAP Designer. The designer supports application developers with the option to automatically generate source code to integrate with SAP objects. For all defined SAP objects in an .erp file, the provider will create a context class which inherits from the ERPDataContext base class. The generated context class contains methods and sub-classes that represent the defined SAP objects. Beside the .erp file, LINQ to SAP designer will save the associated and automatically generated source code in a file with the extension .Designer.cs.

Figure 2: Add new project item

Figure 3: SAP objects in LINQ to SAP Designer

Figure 4: Connection dialog in LINQ to SAP Designer

Function Modules

This section shows how to access and obtain data using the function module BAPI_EQUI_GETLIST by creating a LINQ to SAP object. The module is returning an equipment list for pre-defined plants. First of all one must add a new LINQ to SAP file (.erp) to a new or existing Visual Studio 2008 project. By opening the .erp file the LINQ to SAP Designer will start. By double-clicking on the Function item in the toolbox of Visual Studio will add a new SAP object Function Module. In the next step the object search dialog opens and the developer can search for function modules.

Figure 5: Search dialog in LINQ to SAP Designer

Once the selection is made, the LINQ to SAP Designer will show up the Function Module dialog box with all data, properties and parameter definitions of the selected module BAPI_EQUI_GETLIST. The user can now change the naming of the auto-generated method as well as all used parameters.

Figure 6: Function Module dialog in LINQ to SAP Designer

For each function module the LINQ to SAP Designer will generate a context class method with all additional object classes and structures. If for instance the user defines a method name called GetEquipmentList for the function module BAPI_EQUI_GETLIST, the designer will generate a context class method with that name and the defined method signature. The user can also specify the parameters to exchange. The lower area of the dialog is displaying the SAP typical parameters, like IMPORT, EXPORT, CHANGING and TABLES parameters. LINQ to SAP allows to define default values for SAP parameters. Those parameters can also be used as parameters for the auto-generated context class method as well as for return values. The names for the parameters and the associated structures can also be renamed.

The method signature for the function module defined above looks like this:

public EquipmentTable GetEquipmentList(PlantTable plants)

The context class itself is named SAPContext by default. The context class name, the namespace, the connection settings as well as other flags can be defined in the properties window of the LINQ to SAP Designer. The following code shows how to use the context class SAPContext:

class Program

{

static void Main()

{

SAPContext dc = new SAPContext(„TESTUSER“, „XYZ“);

SAPContext.PlantTable plants = new SAPContext.PlantTable();

SAPContext.PlantStructure ps = plants.Rows.Add();

ps.SIGN = „I“;

ps.OPTION = „EQ“;

ps.LOW = „3000“;

SAPContext.EquipmentTable equipList = dc.GetEquipmentList(plants);

}

}

Tables

The procedure for adding a SAP Table is basically the same as for function modules (see above). After adding the SAP Table object from the toolbox in Visual Studio and finding the table with the search dialog, the Table dialog will show up:

Figure 7: Tables Module dialog in LINQ to SAP Designer

In the upper part of the table dialog the user must define the class name for table object for auto-generation. The default name is the name of the table. The lower part shows a data grid with all table fields and their definitions. For each field a class property name can be defined for the auto-generated context class code. The checkbox in the first column selects if the field will be part of the table class.

The figure above shows the definition of the SAP Table object T001W. This tables stores plant information. The class has not been changed, so the designer will create a C# class with the name T001W. In addition the context class will contain a property T001WList. The type of this property is ERPTable<T001W>, which is LINQ queryable data type.

The following code shows how to query the table T001W using the context class:

class Program

{

static void Main()

{

SAPContext dc = new SAPContext(„TESTUSER“, „XYZ“);

dc.Log = Console.Out;

var res = from p in dc.T001WList

where p.WERKS == „3000“

select p;

foreach (var item in res)

Console.WriteLine(item.NAME1);

}

}

SAP Context Class and Logging

To access objects using LINQ to SQL, the provider will generate a context class named DataContext. Accordingly LINQ to SAP also creates a context class called SAPContext. This class is defined as a partial class. A partial class is a type declaration that can be split across multiple source files and therefore allows developers to easily extend auto- generated classes like the context class of LINQ to SAP.

The code sample below shows how to add a partial class (file SAPContext.cs) which adds a new custom method GetEquipmentListForMainPlant to extend the context class generated by the LINQ to SAP designer. This new method calls internally the auto-generated method GetEquipmentList with a pre-defined parameter value. The C# compiler will internally merge the auto-generated LINQtoERP1.Designer.cs with the SAPContext.cs source file.

using System;

namespace LINQtoSAP

{

partial class SAPContext

{

public EquipmentTable GetEquipmentListForMainPlant()

{

SAPContext.PlantTable plants = new SAPContext.PlantTable();

SAPContext.PlantStructure ps = plants.Rows.Add();

ps.SIGN = „I“;

ps.OPTION = „EQ“;

ps.LOW = „3000“;

return GetEquipmentList(plants);

}

}

}

LINQ to SAP also provides the capability to log LINQ query translations. In order to log data the LOG property of the context class must be set with a TextWriter instance, e.g. the console output Console.Out. All LINQ to SAP does is a very rudimentary logging which is restricted to table objects. But it helps developers to get a feeling about what the translated where part looks like.

Summary

In overall LINQ to SAP is very simple but yet powerful LINQ data provider and Visual Studio 2008 Designer to use. You also get a feeling on how to develop against a SAP/R3 system using .NET. For more information about the product please check out the homepage of the vendor, http://www.theobald-software.com.

I wrote an article about LINQ to SAP at CodeProject.com, a new LINQ provider I developed for the company Theobald Software GmbH in Stuttgart, Germany. This provider allows you to easily connect to SAP/R3 systems using the LINQ technology and a Visual Studio 2008 Designer. LINQ to SAP is part of the ERPConnect software suite that interconnects SAP/R3 systems with .NET. You can find more details here.

A fellow of mine wrote an interesting article about a very nice and useful library called ERPConnect from Theobald Software. It allows .NET developer to easily access SAP systems to query data, execute BAPIs and much more. Have a look!

SharePoint 2010 provides developer with the capability to integrate external data sources like SAP business data via the Business Connectivity Services (BCS) into the SharePoint system. The concept of BCS is based on entities and associated stereotyped operations. This perfectly suits for flat and simple structured data sets like SAP tables.

Another and way more flexible option to use SAP data in SharePoint are the ERPConnect Services for SharePoint 2010 from Theobald Software. The product suite consists of three product components: ERPConnect Services runtime, the BCS Connector application and the Xtract PPS for PerformancePoint Services.

The ERPConnect Services runtime is providing a Service Application that integrates itself with the new service architecture of SharePoint 2010. The runtime offers a secure middle-tier layer to integrate different kind of SAP objects in your SharePoint applications, like tables and function modules.

The BCS Connector application allows developers to quickly create BDC models for the BCS Services, completely without programming knowledge. You even be able to export the BDC models created by the BCS Connector to Visual Studio 2010 for further customizing. The Xtract PPS component offers a SAP data source provider for the PerformancePoint Services of SharePoint 2010.

This article gives you an overview of the ERPConnect Services runtime and shows how easy you can create and incorporate business data from SAP in different SharePoint application types, like Web Parts, Application Pages or Silverlight modules. This article does not introduce the BCS Connector nor the Xtract PPS component.

SAP Background

This section will give you a short explanation and background of SAP objects that can be used in ERPConnect Services for SharePoint 2010. The most important objects are SAP tables and function modules.

A function module is basically similar to a normal procedure in conventional programming languages. Function modules are written in ABAP, the SAP programming language, and are accessible from any other programs within a SAP system. They accept import and export parameters as well as other kind of special parameters. In addition, BAPIs (Business-API) are special function modules that are organized within the SAP Business Object Repository. In order to use function modules with ERPConnect Services they must be marked as Remote (RFC).

SAP tables can also be accessed by ERPConnect Services. Tables in SAP are basically relational database tables. Others SAP objects like BW Cubes or SAP Queries can be accessed via the XtractQL query language (see below).

ERPConnect Services Installation & Configuration

Theobald Software is providing an evaluation version that can be downloaded from their website. Installing the ERPConnect Services on a SharePoint 2010 server is done by an installer and is straight forward. The SharePoint Administration Service must run on the local server (see Windows Services). For more information see product documentation. After the installation has been successfully processed navigate to the Service Applications screen within the central administration (CA) of SharePoint:

Before creating your first ERPConnect Service Application a Secure Store must be created, where ERPConnect Services will save SAP user credentials. There will be a SNC (Secure Network Communication) option for Single-Sign-On (SSO) scenarios starting with the next product version. In the settings page for the "Secure Store Service" create a new Target Application and name the application "ERPConnect Services". Click on the button "Next" to define the store fields as follows:

Click the "ERPConnect Service Application" link in the "New" menu of the Service Applications page (see also first screenshot above). This opens the "Create New ERPConnect Service Application" dialog to define the name of the service application, the SAP connection data and the IIS application pool:

Click "Create" after entering all data and you will see the following entries in the Service Applications screen:

That’s it! You are now done setting up your first ERPConnect Service Application.

ERPConnect Services Development

The ERPConnect Services runtime functionality covers different programming demands such as generically retrievable interface functions. The ERPConnect Services are managed by the Central Administration of SharePoint. The following service and function areas are provided by ERPConnect Services:

1. Executing and retrieving data directly from SAP tables

2. Executing SAP function modules / BAPIs

3. Executing XtractQL query statements

The next sections shows how to use these service and function areas and access different SAP objects from within your custom SharePoint applications using the ERPConnect Services. The runtime can be used in applications within the SharePoint context like Web Parts or Application Pages. In order to do so, you need to reference the assembly ERPConnectServices.Server.Common.dll in the project.

Before you can access data from the SAP system you must create an instance of the ERPConnectServiceClient class. This is the gate to all SAP objects and the generic API of ERPConnect Services runtime in overall. In the SharePoint context there are two options to create a client object instance:

For more details on using ERPConnect Services in Silverlight or desktop applications see the specific sections below.

Querying Tables

Querying and retrieving table data is a common task for developers. ERPConnect Services runtime allows retrieving data directly from SAP tables. The ERPConnectServiceClient class provides a method called ExecuteTableQuery with two overrides which query SAP tables in a simple way. The method also supports a way to pass miscellaneous parameters like row count and skip, custom function, where clause definition and a returning field list. These parameters can be defined by using the ExecuteTableQuerySettings class instance.

The first query reads all records from the SAP table T001 where the fields ORT01 equals Paris and LAND1 equals FR (France). The query returns the top 100 records and the result set contains only the fields BUKRS, BUTXT, ORT01 and LAND1. The second query returns the top ten records of the SAP table MAKT, where the field MATNR equals the material number 60-100C. The result set is ordered by the field SPRAS.

Executing Function Modules

In addition to query SAP tables the runtime API executes SAP function modules (BAPIs). Function modules must be marked as remote-enabled modules (RFC) within SAP. The ERPConnectServiceClient class provides a method called CreateFunction to create a structure of metadata for the function module. The method returns an instance of the data structure ERPFunction. This object instance contains all parameters types (import, export, changing and tables) that can be used with function modules.

In the sample below we call the function SD_RFC_CUSTOMER_GET and pass a name pattern (T*) for the export parameter with name NAME1. Then we call the Execute method on the ERPFunction instance. Once the method has been executed the data structure is updated. The function returns all customers in the table CUSTOMER_T.

The following code shows an additional sample. Before we can execute this function module we need to define a table with HR data as input parameter. The parameters you need and what values the function module is returning dependents on the implementation of the function module.

The ERPConnect Services runtime is offering a new way of accessing SAP data. Theobald Software has developed a SAP query language called XtractQL. The XtractQL query language, also known as XQL, consists of ABAP and SQL syntax elements.

XtractQL allows querying SAP tables, BW-Cubes, SAP Queries and executing function modules. It also returns metadata for the objects and even MDX statements can be executed with XQL. All XQL queries are returning a data table object as result set. In case of the execution of function modules the caller must define the returning table (see sample below – INTO @RETVAL). XQL is very useful in situations where you need to handle dynamic statements. The following list shows a couple of query samples you may use in your applications:

SELECT TOP 5 * FROM T001W WHERE FABKL = ‚US‘

This query selects the top 5 records of the SAP table T001W where the field FABKL equals the value US.

This query selects all records and fields of the SAP table MARA using a custom SAP function module to retrieve the data called Z_XTRACT_IS_TABLE.

SELECT MAKTX AS [ShortDesc], MANDT, SPRAS AS Language FROM MAKT

This query selects all records of the SAP table MAKT. The result set will contains three fields named ShortDesc, MANDT and Language.

EXECUTE FUNCTION ‚SD_RFC_CUSTOMER_GET‘

EXPORTS KUNNR=’0000003340′

TABLES CUSTOMER_T INTO @RETVAL;

This query executes the SAP function module SD_RFC_CUSTOMER_GET and returns as result the table CUSTOMER_T (defined as @RETVAL).

DESCRIBE FUNCTION ‚SD_RFC_CUSTOMER_GET‘ GET EXPORTS

This query returns metadata about the export parameters of the SAP function module.

SELECT TOP 30 LIPS-LFIMG, LIPS-MATNR, TEXT_LIKP_KUNNR AS CustomerID

FROM QUERY ‚S|ZTHEO02|ZLIKP‘

WHERE SP$00002 BT ‚0080011000‘AND ‚0080011999‘

This statement executes the SAP Query "S|ZTHEO02|ZLIKP" (name includes the workspace, user group and the query name). As you can see XtractQL extends the SQL syntax with ABAP or SAP specific syntax elements. This way you can define fields using the LIPS-MATNR format and SAP-like where clauses like "SP$00002 BT ‚0080011000‘AND ‚0080011999‘".

ERPConnect Services for SharePoint 2010 (ECS) provides a little helper tool, the XtractQL Explorer (see screenshot below), to learn more about the query language and to test XQL queries. You can use this tool independent of SharePoint 2010, but you need access to a SAP system.

To find out more about all XtractQL language syntax see the product manual.

ERPConnect Services In Silverlight And Desktop Applications

So far all samples are using the assembly ERPConnectServices.Server.Common.dll as project reference and all code snippets shown run within the SharePoint context, e.g. Web Part. ERPConnect Services runtime also provides client libraries for Silverlight and desktop applications:

You need to add the references depending what project you are implementing.

In Silverlight the implementation and design pattern is a little bit more complicated, since all web services will be called in asynchronously. It’s also not possible to use the DataTable class. It’s just not implemented for Silverlight. ERPConnect Services provides a similar class called ERPDataTable, which is used in this cases by the API.

The ERPConnectServiceClient class for Silverlight provides the method ExecuteTableQueryAsync and an event called ExecuteTableQueryCompleted as callback delegate.

The following code sample shows a simple query of the SAP table T001 within a Silverlight client. First of all, an instance of the ERPConnectServiceClient is created using the URI of the ERPConnectService.svc, then a delegate is defined to handle the complete callback. Next, the query is executed, defined with a RowCount equal 10 to only return the top 10 records in the result set. Once the result is returned the data set will be attached to a DataGrid control (see screenshot below) within the callback method.

ERPConnect Services for SharePoint 2010 product suite includes a Visual Studio 2010 plugin, the ECS Designer, that allows developer to visually design SAP interfaces. It’s working similar to the LINQ to SAP Designer I have written about a while ago, see article at CodeProject: LINQ to SAP.

The ECS Designer is not automatically installed once you install the ERPConnect Services suite. You need to call the installation program manually. The setup adds a new project item type to Visual Studio 2010 with the file extension .ecs and is linking it with the ECS Designer. The needed references are added automatically after adding an ECS project item. The designer generates source code to integrate with the ERPConnect Services runtime after the project item is saved. The generated context class contains methods and sub-classes that represent the defined SAP objects (see screenshots below).

Before you access the SAP system for the first time you will be asked to enter the connection data. You may also load the connection data from SharePoint system. The ECS Designer GUI is shown in the screenshots below:

The screenshot above for instance shows the tables dialog. After clicking the Add (+) button in the main designer screen and searching a SAP table in the search dialog, the designer opens the tables dialog. In this dialog you can change the name of the generated class, the class modifier and all needed properties (fields) the final class should contain. To preview your selection press the Preview button. The next screenshot shows the automatically generated classes in the file named EC1.Designer.cs:

Using the generated code is simple. The project type we are using for this sample is a standard console application, therefore the ECS Designer is referencing the ERPConnectServices.Client.dll for desktop applications. Since we are not within the SharePoint context, we have to define the URI of the SharePoint system by passing this value into the constructor of the ERPConnectServicesContext class.

The designer has generated class MAKT and an access property MAKTList for the context class of the table MAKT. The type of this property MAKTList is ERPTableQuery<MAKT>, which is a LINQ queryable data type. This means you can use LINQ statements to define the underlying query. Internally, the ERPTableQuery<T> type will translate your LINQ query into call of ExecuteTableQuery.

That’s it! SAP access as its best.

Advanced Techniques

There are situations when you have to use the exact same SAP connection while calling a series of function modules in order to receive the correct result. Let’s take the following code:

In this sample we create a goods receipt for a goods movement with BAPI_GOODSMVT_CREATE. The final call to BAPI_TRANSACTION_COMMIT will only work, if the system under the hood is using the same connection object.

The ERPConnect Services is not providing direct access to the underlying SAP connection, but the library offers a mechanism called connection scoping. You may create a new connection scope with the client library and telling ERPConnect Services to use the same SAP connection until you close the connection scope. Within the connection scope every library call will use the same SAP connection.

In order to create a new connection scope you need to call the BeginConnectionScope method of the class ERPConnectServiceClient. The method returns an IDisposable object, which can be used in conjunction with the using statement of C# to end the connection scope. Alternatively, you may call the EndConnectionScope method.

It’s also possible to use function modules with nested structures as parameters. This is a special construct of SAP. The goods receipt sample above is using a nested structure for the export parameter GOODSMVT_CODE. For more detailed information about nested structures and tables see the product documentation.

Summary

ERPConnect Services for SharePoint 2010 is powerful product suite to integrate SAP business data into SharePoint applications. Combining the ERPConnect Services runtime with the BCS Connector tool unleashes the real power of this toolkit. More information about ERPConnect Services for SharePoint 2010 you will find here: